1. Field of the Invention
The present invention relates to a door latch device.
2. Description of the Related Art
A door latch device that holds a door of a vehicle in a closed state includes a base plate having a striker entry groove entered by a striker, a latch rotatably supported on a latch shaft provided on the base plate, and a ratchet rotatably supported on a ratchet shaft provided on the base plate. The latch moves between a full-latch position in which the latch constrains the striker that has entered the striker entry groove by engaging with the striker, and an open position in which the latch releases the constrained striker. The ratchet moves between an engagement position in which the ratchet engages with the latch so as to hold the latch in the full-latch position, and a disengagement position in which the ratchet releases the engagement.
There are such kind of door latch devices (refer, for example, to Japanese Translation of PCT International Application Publication No. 2007-506879) that include a linkage mechanism that is operated by power from a driving member to move the latch to the full-latch position when the latch is moved from the open position into a half-latch position by, for example, a pressing load from the striker that has entered the striker entry groove.
The linkage mechanism includes a first link rotatably supported on a fixed shaft provided on the base plate, a second link rotatably supported on the latch shaft, and an intermediate link that is rotatably connected to the first link by a first link shaft and rotatably connected to the second link by a second link shaft. In the linkage mechanism, introducing the power from the driving member to the first link rotates the second link about the latch shaft so as to move the latch to the full-latch position.
In the door latch device disclosed in Japanese Translation of PCT International Application Publication No. 2007-506879, the first link, the second link, the intermediate link, and the driving member are arranged in an area on one side of a plane, serving as a boundary, including a shaft center of the fixed shaft and a shaft center of the latch shaft (hereinafter also called “boundary plane”). This necessitates a large space for arranging the linkage mechanism and the driving member on one area side of the boundary plane, and thus makes it difficult to reduce the size of the door latch device.